Safety device for a pre-filled syringe and injection device

ABSTRACT

A safety device for a pre-filled syringe comprises a hollow support body to retain the pre-filled syringe, a retaining collar and a rotating collar arranged within the support body. The retaining collar is releasably mounted to the support body. The rotating collar is slidable along an axial length of the support body and rotatable around a central axis of the safety device. The retaining collar is movable with respect to the support body in a proximal direction when the retaining collar is released from being mounted to the support body by the rotating collar.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Phase application pursuant to35 U.S.C. §371 of International Application No. PCT/EP2011/060322 filedJun. 21, 2011, which claims priority to European Patent Application No.10168322.5 filed on Jul. 2, 2010. The entire disclosure contents ofthese applications are herewith incorporated by reference into thepresent application.

FIELD OF INVENTION

The present invention relates to safety devices that provide needlesafety and more particularly to safety devices for pre-filled syringes.The safety device is adapted to avoid accidental needle stick injuriesand needle injuries before, during and after an injection of amedication or drug contained in the pre-filled syringe. In particular,the safety device provides needle safety for a subcutaneousself-administrated injection or for an injection administered by ahealth-care professional. The present invention further relates toinjection devices comprising a pre-filled syringe.

BACKGROUND

Pre-filled syringes that are filled with a selected dosage of amedication are well known injection devices for administering themedication to a patient. Safety devices for covering a needle of apre-filled syringe before and after use are also well known. Typically,these devices comprise a needle shield that is either manually moved ormoved by the action of a relaxing spring to surround the needle.

A different type of safety devices known in the state of the art solvesthe object of providing needle safety by arranging the pre-filledsyringe movable relative to a body, whereas the pre-filled syringe isretracted into the body after the injection.

SUMMARY

It is an object of the present invention to provide an improved safetydevice for a pre-filled syringe.

It is a further object of the invention to provide an improved injectiondevice comprising a pre-filled syringe that is safe to handle and inparticular prevents accidental needle stick injuries.

The object is achieved by a safety device according to claim 1 and by aninjection device according to claim 14.

Preferred embodiments of the invention are given in the dependentclaims.

In the context of this patent, the terms distal and proximal are definedfrom the point of view of a person performing an injection.Consequently, a distal direction refers to a direction pointing towardsthe body of a patient receiving an injection and a distal end defines anend of an element that is directed towards the body of the patient.Respectively, the proximal end of an element or the proximal directionis directed away from the body of the patient receiving the injectionand opposite to the distal end or distal direction.

A safety device for a pre-filled syringe comprises a hollow support bodyto retain the pre-filled syringe, a retaining collar and a rotatingcollar arranged within the support body. The retaining collar isreleasably mounted to the support body. The rotating collar is slidablealong an axial length of the support body and rotatable around a centralaxis of the safety device. The retaining collar is movable with respectto the support body in a proximal direction when the retaining collar isreleased from being mounted to the support body by the rotating collar.

The location and angular orientation of the rotating collar relative tothe support body arms and activates safety features of the safetydevice, such as arming a release and retraction mechanism. The rotatingcollar releases the retaining collar from being mounted to the supportbody after a single injection stroke has been performed. With thepre-filled syringe mounted to the retaining collar, the release of theretaining collar and the following proximal movement of the retainingcollar relative to the support body results in a retraction of thepre-filled syringe with respect to the support body. The rotating collarallows for a convenient use of the safety device avoiding accidentalneedle pricks caused by a hypodermic needle of the pre-filled syringeinserted into the support body of the safety device.

As the rotating collar is rotatable and slidable within the support bodybetween different positions, a relative rotation of any external partsof the safety device during an injection is avoided. In particular whenthe hypodermic needle still penetrates the skin of a patient receivingthe injection, unnecessary pain might be caused to the patient ifcomplicated movements like rotation of external parts have to beexecuted to activate the safety features of the safety device. Thesafety features of the safety device according to the invention areconveniently activated by a user performing a single linear injectionstroke.

The rotating collar comprises a central opening for the reception of thepre-filled syringe therein and at least one outwardly protruding guidepin that protrudes through a guide track formed into the support body.The guide pin moves within and along the guide track during theinjection, whereas the guide track comprises an inclined section that isoriented at an acute angle relative to the central axis of the safetydevice. When the guide pin is moved along the inclined section, therotating collar rotates within the support body around the central axisand changes its angular orientation. This change of angular orientationallows the rotating collar to bear against and release a retainingcollar mounting the pre-filled syringe relative to the support body. Therelease of the retaining collar occurs automatically after a singlelinear injection stroke has been carried out. No additional interactionor attention is required from the user of the safety device performingthe injection stroke to arm and activate the release and retractionmechanism. For safety reasons, the safety device is automaticallyprevented from being re-used after the single linear injection strokehas been carried out.

An outer body is manually moved relative to the support body by a userof the safety device performing the injection stroke. The outer bodyabuts the outwardly protruding guide pin, so that the rotating collarjointly moves together with the outer body parallel a central axis ofthe safety device and along a substantial axial length of the supportbody. This simple mechanism couples the linear axial movement of theouter body relative to the support body in particular during theinjection stroke to the movement of the rotating collar within thesupport body, whereby the safety features of the safety device are armedand activated.

An inclined section of the guide track is oriented at an acute anglerelative to the central axis. The guide pin protruding through the guidetrack is pushed by the outer body along the inclined section of theguide track, whereby the guide pin moves both in a lateral and in theaxial direction parallel to the central axis. Simultaneously, therotating collar rotates within the support body and changes its angularorientation relative to the support body, so that the guide pin isprevented to travel back into the inclined section of the guide track,whereby a re-usage of the safety device is prevented. Thus, the safetydevice is designed to be used in combination with disposable pre-filledsyringes and prevents needle stick injuries with contaminated hypodermicneedles.

The inclined section of the guide track is connected to a parallelsection of the guide track extending parallel to the central axis by anarrowed section. The narrowed section is limited by a flexing gateelement that is resiliently deflectable allowing for at least a one-waytransition of the guide pin from the inclined section to the parallelsection of the guide track. The guide pin is prevented to travel backinto the inclined section from a proximal direction. The flexing gateelement is an additional means to prevent the re-usage of the device.

In one embodiment of the invention, the safety device produces anaudible feedback when the guide pin passes the flexing gate element inthe narrowed section. Thus, the safety device generates a feedbackindicating that the release and retraction mechanism is armed to allowfor a retraction of the pre-filled syringe within the support body.

A spring is arranged within the support body that bears against therotating collar, whereby the rotating collar is biased in a proximaldirection. Initially, the spring is in a partially energized state.During the injection stroke, the rotating collar moves in the distaldirection, whereby the spring energized and charged. The spring is thusfully charged only for a short period of time during the use of thesafety device, so that the pre-filled syringe can be retracted by theaction of the relaxing spring. The spring is only partially chargedduring shipment and storage of the safety device, which in turn avoidsmaterial fatigue and thus increases the shelf-life of safety device.

According to a further embodiment of the invention, the needle shield isslidably arranged within the support body. The spring is arranged withinthe support body between the rotating collar and the needle shield, sothat the needle shield is biased in a distal direction. The needleshield surrounds the hypodermic needle before the injection to avoid orreduce a possible patient's fear of needles. The safety device isdesigned in a manner that the hypodermic needle of the pre-filledsyringe is never exposed before or after the injection. The safetydevice is thus particularly suited for performing self-administeredsubcutaneous or intramuscular injections. Consequently, the user of thesafety device and/or injection device can be one and the same person.

According to the same embodiment, the needle shield has a centralaperture of variable diameter. Preferably, the needle shield is madefrom a flexible material. Before usage of the device a needle capcovering the hypodermic needle protrudes through the central aperture ofthe needle shield. After removal of the needle cap, the central aperturerelaxes and relieves to form a central aperture of reduced diameter dueto the memory of the flexible material of the needle shield. Thiscentral aperture of reduced diameter additionally reduces the risk of aninadvertent contact with the hypodermic needle. Furthermore, an axialdistance by which the needle shield has to protrude the support body toensure needle safety can be reduced.

Preferably, the needle shield is made by the process of a two-shotinjection moulding. The combination of a relative rigid and a relativesoft material allows the needle shield to retain its substantialcylindrical shape whilst being able to stretch over the needle cap.

According to another embodiment of the invention, the retaining collarcomprises at least one ratchet arm that latches to a locking cut-outformed into the outer body to lock the retaining collar relative to theouter body. Thus, the retaining collar locked to the outer body can bereleased from being mounted to the support body and be moved in aproximal direction with respect to the support body by a proximalmovement of the outer body. The outer body moves proximally by theaction of the relaxing spring, whereas the biasing force of the relaxingspring is transferred to the outer body via the rotating collar and theguide pin abutting the outer body. In this embodiment of the invention,the retraction mechanism is advantageously combined with a lockingfeature of the outer body, so that a re-exposure of the hypodermicneedle is prevented and a subsequent injection stroke following thefirst injection stroke is prevented.

According to the same embodiment of the invention, the outer bodycomprises a plurality of locking cut-outs that are axially displacedrelative to each other. As the outer body is slid with respect to thesupport body to inject the medication, the ratchet arm locks into one ofthe locking cut-outs that corresponds to the axial displacement of theouter body with respect to the support body. The outer body is thuslocked to the retaining collar. When the ratchet arm locks to thelocking recess located at a proximal end of the outer body, the safetydevice automatically becomes needle safe after the safety device hasbeen removed from the injection site.

According to yet another embodiment, a guide rail is formed into aninner surface of the outer body. The guide rail guides the guide pin inparticular along the inclined section of the guide track to rotate therotating collar within the support body, so that the release andretraction mechanism of the safety device is activated.

The guide rail comprises a first section that is oriented at an angleless than 90 degrees with respect to the central axis and a secondsection that substantially extends parallel to the central axis. Thefirst section of the guide rail abuts the guide pin when the outer bodyis slid relative to support body to perform the injection stroke. Theorientation of the first section relative to the central axis supportsthe rotating movement of the rotating collar within the support body.

An injection device comprises a pre-filled syringe retained in thesupport body of the safety device. The pre-filled syringe comprises ahypodermic needle attached to a distal end of the pre-filled syringe, abarrel with an inner cavity in fluid communication with the hypodermicneedle and a piston fluid-tightly sealing a proximal end of the innercavity. The pre-filled syringe is releasably mounted by the mountingmeans within the support body of the safety device, so that thepre-filled syringe can be retracted to cover the hypodermic needle afterthe injection. The injection device comprising the pre-filled syringeand the safety device combines the aforementioned advantages and avoidsinadvertent needle sticks before, during and after an injectiondelivering the medication beneath the skin of a patient.

According to a possible embodiment, the ratchet arm locks into thelocking cut-out that corresponds to a piston stroke length of the pistonwithin the barrel of the pre-filled syringe as the outer body is slidwith respect to the support body to inject the medication. A userperforming the injection can visually verify which locking cut-out isoccupied by the ratchet arm, which in turn indicates the piston strokelength and thus an amount of medication left in an inner cavity of thepre-filled syringe retained in the safety device.

Details of the present invention are described hereinafter. However, itshould be understood that the detailed description and the specificexamples indicate possible embodiments of the invention and are given byway of illustration only. Various changes and modifications of theillustrated embodiments within the spirit and scope of the invention areappreciated by those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from the detaileddescription given in the following. The accompanying drawings are givenfor illustrative purposes only and do not limit the scope of the presentinvention.

FIG. 1 shows a perspective view of an injection device according to afirst embodiment of the invention in a packaged state.

FIG. 2 shows a detailed view of a distal end of the support body withthe needle shield retained therein.

FIG. 3 shows a sectional view of the injection device according to thefirst embodiment before the injection.

FIG. 4 shows a sectional view of the injection device according to thefirst embodiment and illustrates a cross-section perpendicular to thecross-section shown in FIG. 3.

FIGS. 5A to 5C show perspective views of different embodiments of arotating collar.

FIG. 6 shows a side view of a support body with a guide track.

FIG. 7 shows details of an inner surface of an outer body of the safetydevice.

FIG. 8 illustrates schematically the movement of a guide pin within theguide track.

FIG. 9 shows a sectional view of an injection device at the end of theinjection stroke corresponding to the cross-section shown in FIG. 4.

FIG. 10 shows a sectional view of the injection device in a final stateafter the injection has been performed corresponding to thecross-section shown in FIG. 4.

FIGS. 11 to 14 show perspective and sectional views of an injectiondevice according to a second embodiment of the invention.

Corresponding parts are marked with the same reference symbols in allfigures.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of an injection device D with a safetydevice 1 according to a first embodiment of the invention. The injectiondevice D is in a packaged state as it would be presented to an end-user.

The safety device 1 comprises a needle shield 1.1 that is substantiallyreceived within an open distal end of a tubular support body 1.2 priorto use of the safety device 1. A proximal end of the support body 1.2 isreceived in an open distal end of a hollow outer body 1.3, whereas theouter body 1.3 is slidable relative to the support body 1.2.

Two wing-shaped gripping means 1.3.1 protrude the outer body 1.3 in aradial outward direction perpendicular to a central axis A of the safetydevice 1. The gripping means 1.3.1 are moulded to opposite sides of theouter body 1.3. The gripping means 1.3.1 are designed to support a handof a user of the safety device 1 during the injection stroke.Alternatively, the gripping means 1.3.1 may be designed as an annularflange.

The support body 1.2 comprises two longitudinal tongues 1.2.1 protrudingopposite sides of the support body 1.2 in a radial outward direction.The longitudinal tongue 1.2.1 extends along a substantial length of thesupport body 1.2. Each longitudinal tongue 1.2.1 is received in acorresponding longitudinal groove 1.3.2 shown in FIGS. 4 and 7. Thelongitudinal groove 1.3.2 is formed into an inner surface of the outerbody 1.3, so that a rotation of the outer body 1.3 relative to thesupport body 1.2 is prevented when the outer body 1.3 is moved relativeto the support body 1.2.

At least one guide track 1.2.2 is formed into the support body 1.2 thataccommodates a guide pin 1.4.1 extending radial outwardly from arotating collar 1.4 arranged within the support body 1.2. The rotatingcollar 1.4 with the guide pin 1.4.1 is shown in detail in FIGS. 5A to5C.

According to the first embodiment of the safety device 1 shown in FIG.1, two guide tracks 1.2.2 are formed into opposite sides of the supportbody 1.2, whereas each guide track 1.2.2 receives a guide pin 1.4.1 ofthe rotating collar 1.4.

The injection device D comprises the safety device 1 with a pre-filledsyringe 2 retained in the support body 1.2. The pre-filled syringe 2comprises a hypodermic needle 2.1 that is covered by a needle cap 2.2prior to use. The pre-filled syringe 2 is retained within the supportbody 1.2, so that the needle cap 2.2 covering the hypodermic needle 2.1protrudes the support body 1.2 in a distal direction and can be easilygripped and manually removed before use of the injection device D.

Before the injection is carried out, the needle shield 1.1 is retainedin a first position I within the support body 1.2, whereas the needleshield 1.1 in the first position I is substantially received within thesupport body 1.2. The needle shield 1.1 is made from flexible material,especially from two different plastics materials of differentflexibility. Preferably, the needle shield 1.1 is constructed by theprocess of a two shot injection moulding.

The combination of a relative rigid and a relative material allows theneedle shield 1.1 to retain its substantial cylindrical shape whilstbeing able to stretch over the needle cap 2.2 covering the hypodermicneedle 2.1 of the pre-filled syringe 2 prior to use.

The distal end surface 1.1.1 comprises a central aperture 1.1.3 centredon the central axis A. The central aperture 1.1.3 has a diameter ofvariable width. In the packaged state shown in FIG. 1, the flexiblematerial of distal end surface 1.1.1 is stretched over the needle cap2.2 protruding the needle shield 1.1 in the distal direction. A firstdiameter D1 of the central aperture 1.1.3 corresponds to an outerdiameter of the needle cap 2.2.

Additionally, the needle cap 2.2 frictionally engages the needle shield1.1 to retain the needle shield 1.1 in the first position I.

After removal of the needle cap 2.2, the flexible material of the distalend surface 1.1.1 expands and unbends as a consequence of the stressrelief, which results in a central aperture 1.1.3 with a reduced seconddiameter D2 as illustrated in FIG. 2.

FIG. 2 shows a detailed view of a distal end of the support body 1.2with the needle shield 1.1 retained therein. The distal end surface1.1.1 of the needle shield 1.1 is made from a flexible material. Thelateral surface 1.1.2 of the substantially cylindrical needle shield 1.1is made from a relative rigid and stiff plastics material.

During the injection, the needle shield 1.1 is moved to a secondposition II, so that the hypodermic needle 2.1 protrudes through thecentral aperture 1.1.3 with reduced second diameter D2 to dispose amedication beneath the skin of a patient.

Alternatively, the needle shield 1.1 may be retained in a secondposition II prior the injection, wherein the needle shield 1.1 in thesecond position II protrudes the support body 1.2 distally prior to useof the safety device 1.

FIG. 3 shows a sectional view of the injection device D according to thefirst embodiment before the injection. The rotating collar 1.4 isarranged within the support body 1.2, whereas the rotating collar 1.4 isslidable along a substantial axial length of the support body 1.2. Therotating collar 1.4 is retained in an initial position PI within thesupport body 1.2 adjacent to a retaining collar 1.5 releasably mountedto the proximal end of the support body 1.2. The retaining collar 1.5mounts the pre-filled syringe 2 relative to the support body 1.2.

The pre-filled syringe 2 retained within the support body 1.2 comprisesa barrel 2.3 with an inner cavity 2.3.1 containing a medication, apiston 2.4 fluid tightly sealing a proximal end of the inner cavity2.3.1 and a piston rod 2.5 connected to the piston 2.4, whereas thepiston 2.4 is movable at least in the distal direction by actuating thepiston rod 2.5. A circumferential barrel collar 2.3.2 is formed to aproximal end of the barrel 2.3.

Alternatively, the piston rod 2.5 is arranged with the outer body 1.3 asone piece.

The barrel collar 2.3.2 protrudes in the radial outward direction. Theretaining collar 1.5 comprises two opposing outer arms 1.5.1 that extendparallel to the central axis A. An inward projection 1.5.1.1 is formedto a proximal end of each outer arm 1.5.1. The inward projections1.5.1.1 protrude in a radial inward direction and clamp to the barrelcollar 2.3, so that a proximal movement of the pre-filled syringe 2 withrespect to the retaining collar 1.5 is prevented.

A spring 1.6 is arranged within the support body 1.4 between the needleshield 1.1 and the rotating collar 1.4 in a partially energized state.The spring 1.6 bears against the needle shield 1.1 in the distaldirection and against the rotating collar 1.4 in the proximal direction,so that needle shield 1.1 and rotating collar 1.4 is biased away fromeach other.

A guide rail 1.3.3 is formed into the inner surface of the outer body1.3 that abuts the guide pin 1.4.1 protruding through the guide track1.2.2 of the support body 1.2. The guide rail 1.3.3 guides the movementof the guide pin 1.4.1 along and within the guide track 1.2.2 when theouter body 1.3 is moved relative to the support body 1.2.

An inner axial recess 1.3.4 is formed into the inner surface of theouter body 1.3. The inner axial recess 1.3.4 extends parallel to thecentral axis A and over a substantial length of the outer body 1.3. Anoutwardly protruding guiding projection 1.2.6 connected to the supportbody 1.2 moves within and along the inner axial recess 1.3.4 to preventa relative rotation between the outer body 1.3 and the support body 1.2and to limit a proximal movement of the outer body 1.3 with respect tothe support body 1.2.

FIG. 4 shows a sectional view of the injection device D according to thefirst embodiment and illustrates a cross-section perpendicular to thecross-section shown in FIG. 3. The retaining collar 1.5 comprises twoinner arms 1.5.2 opposite to each other. The inner arms 1.5.2 extendparallel to the central axis A and are deflectable in at least theradial inward direction.

An outward projection 1.5.2.1 is formed to the proximal end of the innerarm 1.5.2. The outward projection 1.5.2.1 comprises an inclined outersurface 1.5.2.2 oriented at an acute angle relative to the central axisA that faces and abuts a corresponding inclined inner surface 1.2.3formed to the proximal end of the support body 1.2. The inclined innersurface 1.2.3 and the inclined outer surface 1.5.2.2 are oriented in amanner that the inner arm 1.5.2 is deflected in a radial inwarddirection when the retaining collar 1.5 is moved with respect to thesupport body 1.2 in the proximal direction.

Before the injection, the pre-filled syringe 2 is retained within thesupport body 1.2 in an advanced position PA, in which the hypodermicneedle 2.1 protrudes the support body 1.2 in the distal direction. Thebarrel collar 2.3.2 of pre-filled syringe 2 in the advanced position PAabuts the proximal end of the support body 1.2 and a proximal surface1.5.2.3 of the outward projection 1.5.2 in the distal direction, so thata distal movement of the pre-filled syringe 2 with respect to thesupport body 1.2 is prevented.

FIGS. 5A to 5C show perspective views of different embodiments of therotating collar 1.4. The rotating collar 1.4 comprises a central opening1.4.2 that comprises a diameter that corresponds to or is slightlybigger than a corresponding outer diameter of the barrel 2.3 of thepre-filled syringe 2, so that the rotating collar 1.4 can be moved alonga substantial axial length of the barrel 2.3 and rotated relative to thepre-filled syringe 2 when the pre-filled syringe 2 is retained withinthe safety device 1.

FIG. 5A shows a ring-shaped rotating collar 1.4. Two guide pins 1.4.1are formed to the rotating collar 1.4 at opposite sides. Each guide pin1.4.1 extends in the radial outward direction.

FIGS. 5B and 5C show alternative tubular-shaped embodiments of therotating collar 1.4. The rotating collar 1.4 has a shape similar to ahollow cylinder.

Additionally, the rotating collar 1.4 according to FIGS. 5B and 5Ccomprises a bearing surface 1.4.2 formed to the substantiallycylindrical rotating collar 1.4. The spring 1.6 arranged within thesupport body 1.2 bears against the bearing surface 1.4.2 to bias therotating collar in the proximal direction.

In the embodiment of the rotating collar 1.4 shown in FIG. 5B, thebearing surface 1.4.2 is formed to a distal end of the rotating collar1.4 and has the shape of a circumferential and inwardly protrudingcollar. The rotating collar 1.4 comprises an outwardly protrudingproximal rim 1.4.3 located at a proximal end of the rotating collar 1.4.The proximal rim 1.4.3 engages an inner surface of the support body 1.2and is formed to the rotating collar 1.4 to minimize the frictionbetween the rotating collar 1.4 and the support body 1.2 when therotating collar 1.4 is moved within and/or rotated relative to thesupport body 1.2. The guide pin 1.4.1 is connected to the rotatingcollar 1.4 in a manner that allows for a resilient inward deflection ofguide pin 1.4.1 when the rotating collar 1.4 is assembled within thesupport body 1.2.

FIG. 5C shows another alternative embodiment of the rotating collar 1.4.The bearing surface 1.4.2 is formed to an inner surface of thesubstantially cylindrical rotating collar 1.4 at the proximal end. Thebearing surface 1.4.2 comprises two arc-shaped segments opposing eachother. An outer surface of the rotating collar 1.4 is in contact withthe inner surface of the support body 1.2 during use of the safetydevice 1. The outer surface of the rotating collar 1.4 has asubstantially cylindrical shape and extends over an increased axiallength in comparison to the embodiments shown in FIGS. 5A and 5B. Thisreduces the potential for the rotation collar 1.4 to jam in the supportbody 1.2.

FIG. 6 shows a side view of the support body 1.2 with the guide track1.2.2. The guide pin 1.4.1 integral with the rotating collar 1.4protrudes through the guide track 1.2.2. The guide track 1.2.2 hasessentially a Y-shaped form and comprises an inclined section 1.2.2.1oriented at an acute angle relative to the central axis A and an axialsection 1.2.2.2 extending parallel to the central axis A along asubstantial length of the support body 1.2. Alternatively, the guidetrack 1.2.2 may have a U-shaped form.

The inclined section 1.2.2.1 is connected to the axial section 1.2.2.2by a narrowed section that is limited by a flexing gate element 1.2.4that protrudes into the guide track 1.2.2. The flexing gate element1.2.4 is resiliently deflectable in a lateral direction perpendicular tothe central axis A in at least one direction to allow the guide pin1.4.1 to pass from the inclined section 1.2.2.1 to the axial section1.2.2.2 of the guide track 1.2.2.

Before the injection, the guide pin 1.4.1 is retained in a startposition PS located at a proximal end of the inclined section 1.2.2.1,so that the rotating collar 1.4 is retained in the initial position PIwithin the support body 1.2.

The guide rail 1.3.3 formed into the inner surface of the outer body 1.3abuts the guide pin 1.4.1 during the injection to move and guide theguide pin 1.4.1 along the guide track 1.2.2.

FIG. 7 shows details of the inner surface of the outer body 1.3. In FIG.7, the outer body 1.3 is shown cut open along the longitudinal grooves1.3.2 for better illustration of the inner features of the outer body1.3.

The guide rail 1.3.3 formed into the inner surface of the outer body 1.3comprises a first section 1.3.3.1 that is oriented at an angle less than90 degrees and a second section 1.3.3.2 that extends essentiallyparallel to the central axis A. The first section 1.3.3.1 of the guiderail 1.3.3 abuts the guide pin 1.4.1 of the rotating collar 1.4.

The injection is carried out as follows: The user performing theinjection manually removes the needle cap 2.2, as shown in FIG. 1,protruding a distal end of the safety device 1, whereby the distal endsurface 1.1.1 relaxes and unbends to form the central aperture 1.1.3 ofreduced diameter D2, as illustrated in FIG. 3.

Upon removal of the needle cap 2.2, the spring 1.6 relaxes and moves theneedle shield 1.1 from the first position I to the second position II,so that the hypodermic needle 2.1 is surrounded by the needle shield1.1.

Alternatively, the needle shield 1.1 may be retained in the secondposition II prior the injection.

The injection device D comprising the safety device 1 with thepre-filled syringe 2 retained therein is then put onto a skin surface ofa patient, so that the central axis A of the safety device 1 isorientated essentially perpendicular to the skin surface of a patientand the distal end surface 1.1.1 of the needle shield 1.1 rests onto theskin surface of the patient. A proximal end section of the outer body1.3 is gripped and pushed distally parallel to the central axis Atowards the skin surface to carry out the injection stroke.

The distal surface 1.1.1 is pressed proximally against the biasing forceof the spring 1.6 whereby the needle shield 1.1 moves from the secondposition II to the first position I and the hypodermic needle 2.1penetrates the skin of the patient. At the same time, the closedproximal end of the outer body 1.3 abuts the proximal end of the pistonrod 2.5, so that the piston 2.4 can be pushed in a distal direction bymoving the outer body 1.3 towards the skin surface to expel themedication contained in the inner cavity 2.3.1 through the hypodermicneedle 2.1.

As shown in FIG. 6, the first section 1.3.3.1 of the guide rail 1.3.3abuts the guide pin 1.4.1 that is located in the start position PPSwithin the guide track 1.2.2 at the beginning of the injection stroke.The guide pin 1.4.1 in the start position PPS retains the rotatingcollar 1.4 within the support body 1.2 in the initial position PI. Theouter body 1.3 is pushed distally towards the skin surface, whereby theguide pin 1.4.1, the rotating collar 1.4 and the outer body 1.3 jointlymove in the distal direction.

The guide pin 1.4.1 is pushed along the inclined section 1.2.2.1 of theguide track 1.4, whereby the rotation collar 1.4 rotates within thesupport body 1.2 around the central axis A and changes its angularorientation relative to the support body 1.2. As indicated in FIG. 8,the guide pin 1.4.1 is pushed past the flexing gate element 1.2.4 andpasses the section of narrowed width connecting the inclined section1.2.2.1 and the axial section 1.2.2.2 of the guide track 1.2.2, wherebythe flexing gate element 1.2.4 is resiliently and laterally deflected.

In a possible embodiment of the invention, the safety device 1 producesan audible feedback when the guide pin 1.4.1 passes the flexing gateelement 1.2.4 to indicate that the release and retraction mechanism ofthe safety device 1 is activated. The audible feedback can be producedby the resiliently deflectable flexing gate element 1.2.4 that snapsback into place when the guide pin 1.4.1 passed the narrowed section ofthe guide track 1.2.2.

The guide pin 1.4.1 is further pushed along the axial section 1.2.2.2 inthe distal direction towards an intermediate position PPI by the distalmovement of the outer body 1.3. Simultaneously, the rotating collar 1.4is pushed distally against the biasing force of the spring 1.6 towards adistal position PD and the medication contained in the inner cavity2.3.1 is disposed beneath the skin of the patient.

FIG. 8 illustrates schematically the movement of the guide pin 1.4.1within the guide track 1.2.2. For illustrative purposes, the extensionof the guide rail 1.3.3 is indicated by a doted line.

When the guide pin 1.4.1 reaches the intermediate position PPI locatedat the distal end of the axial section 1.2.2.2 of the guide track 1.2.2at the end of the injection stroke, the medication has been completelyexpelled through the hypodermic needle 2.1. The rotating collar 1.4 isretained in the distal position PD corresponding to the intermediateposition PPI of the guide pin 1.4.1 within the guide track 1.2.2.

FIG. 9 shows a sectional view of the injection device D with a safetydevice 1 at the end of the injection stroke corresponding to thecross-section shown in FIG. 4. With the needle shield 1.1 retained inthe first position I and the rotating collar 1.4 positioned in thedistal position PD located in proximity of the distal end of the supportbody 1.2, the spring 1.6 is fully charged and fully energized. The userperforming the injection therefore has to counteract the biasing forceexerted on the needle shield 1.1 and the rotating collar 1.4 by thespring 1.6 to hold the needle shield 1.1 in the first position I and therotating collar 1.4 in the distal position PD. This is done by pushingthe outer body 1.3 in the distal direction while the distal end surface1.1.1 rests onto the skin surface of the patient.

Upon removal of the injection device D from the injection site, thespring 1.6 relaxes and moves the needle shield 1.1 to the secondposition II. At the same time, the rotating collar 1.4 is moved by theaction of the relaxing spring 1.6 in the proximal direction towards aproximal position PP. As the guide pin 1.4.1 of the rotating collar 1.4abuts the guide rail 1.3.3, the outer body 1.3 jointly moves with therotating collar 1.4 in the proximal direction with respect to thesupport body 1.2.

As best seen in FIG. 8, the guide pin 1.4.1 travels from theintermediate position PPI along the axial section 1.2.2.2 of the guidetrack 1.2.2 in the proximal direction towards an end position PPE. Theflexing gate element 1.2.4 prevents the guide pin 1.4.1 from re-enteringthe start position PPS, so that the guide pin 1.4.1 travels further inthe proximal direction until the guide pin 1.4.1 abuts a proximal end ofthe guide track 1.2.2, so that the guide pin 1.4.1 is retained in theend position PPE.

The rotating collar 1.4 jointly moves within the support body 1.2 in theproximal direction. On the way towards the proximal position PPcorresponding to the end position PPE of the guide pin 1.4.1, therotating collar 1.4 bears against the retaining collar 1.5 in theproximal direction. The inclined inner surface 1.2.3 of the support body1.2 abutting the inclined outer surface 1.5.2.2 causes the inner arm1.5.2 of the retaining collar 1.5 to be radial inwardly deflected,whereby the retaining collar 1.5 is released from being mounted withinthe support body 1.2. The retaining collar 1.5 is pushed further in theproximal direction, whereby the pre-filled syringe 2 mounted to theretaining collar 1.5 is retracted.

FIG. 10 shows a sectional view of the injection device D with the safetydevice 1 in a final state after the injection has been performed. Therotating collar 1.4 reaches the proximal position PP, wherein theretaining collar 1.5 mounting the pre-filled syringe 2 protrudes thesupport body 1.2 in the proximal direction. The pre-filled syringe 2 isretained in a retracted position PR, whereby the hypodermic needle 2.1of the pre-filled syringe 2 is surrounded by the support body 1.2. Aproximal part of the pre-filled syringe 2 in the retracted position PRis covered by the hollow outer body 1.3. A re-exposure of the hypodermicneedle 2.1 is prevented by the biasing force exerted onto the rotatingcollar 1.4 by the spring 1.6 in the proximal direction that istransferred to the pre-filled syringe 2 via the retaining collar 1.5.

FIGS. 11 to 14 show an injection device D with a safety device 1according to a second embodiment of the invention.

FIG. 11 shows a perspective view of the injection device D with thesafety device 1 according to the second embodiment before the injection.The outer body 1.3 comprises opposite longitudinal grooves 1.3.2 formedby outwardly protruding longitudinal bulge in the surface of the outerbody 1.3.

A plurality of locking cut-outs 1.3.5 are formed into the outer body 1.3that are aligned parallel to the central axis A and axially displacedfrom each other.

FIG. 12 shows a sectional view of the safety device 1 according to thesecond embodiment prior to use. The needle cap 2.2 covering thehypodermic needle 2.1 protrudes the support body 1.2 in the distaldirection.

The retaining collar 1.5 comprises a ratchet arm 1.5.3 that latches tothe locking cut-out 1.3.5 located at a distal end of the outer body 1.3,whereby an axial displacement of the retaining collar 1.5 with respectto the outer body 1.3 in the distal direction is prevented and an axialdisplacement of the retaining collar 1.5 with respect to the outer body1.3 in the proximal direction is allowed.

Furthermore, the retaining collar 1.5 comprises a plurality of outwardprojections 1.5.2.1 that are axially displaced from each other.

The spring 1.6 arranged within the support body 1.2 bears against adistal inner surface of the support body 1.2 and the rotating collar 1.4to bias the rotating spring 1.6 with respect to the support body 1.2 ina proximal direction.

FIG. 13 shows the injection device D according to the second embodimentat the end of the injection stroke. The spring 1.6 is fully charged andfully energized.

The injection device D with the safety device 1 according to the secondembodiment is used in an injection as follows: After removal of theneedle cap 2.2, the hypodermic needle 2.1 protruding the support body1.2 penetrates the skin of the patient at the injection site.

A distal end surface 1.2.5 of the support body 1.2 rests on the skin ofthe patient during the injection. The outer body 1.3 is moved towardsthe skin surface of the patient in the distal direction, whereby themedication contained in the inner cavity 2.3.1 is expelled.

During the distal movement of the outer body 1.3 with respect to thesupport body 1.2 and the retaining collar 1.5 releasably affixed to thedistal end of the support body 1.2, the ratchet arm 1.5.3 latches to oneof the locking cut-outs 1.3.5 corresponding to the piston stroke lengthof the piston 2.4 within the barrel 2.3. The user can visually confirmwhich of the locking cut-outs 1.3.5 is occupied from outside, and thusgets an indication of the displacement of the piston 2.4 within thebarrel 2.3 and correspondingly an indication of an amount of medicationleft in the inner cavity 2.3.1 of the barrel 2.3.

For clear visual indication, the ratchet arm 1.5.3 may be coloureddifferently from the outer body 1.3.

The interaction of the ratchet arm 1.5.3 with the locking cut-out 1.3.5blocks a proximal movement of the outer body 1.3 with respect to theretaining collar 1.5. Therefore, the retaining collar 1.5 is releasedfrom being mounted to the support body 1.2 when the outer body 1.3 ismoved with respect to the support body 1.2 in the proximal direction.

FIG. 13 shows the injection device D with the safety device 1 at the endof the injection stroke. The spring 1.6 fully charged. When theinjection device D is removed from the injection site, the spring 1.6relaxes and moves the rotating collar 1.4 in the proximal direction. Atthe same time, the outer body 1.3 locked to the retaining collar 1.5 ismoved proximally, as the guide pin 1.4.1 of the rotating collar 1.4abuts the guide rail 1.3.3 formed into inner surface of the outer body1.3. The retaining collar 1.5 is released from being mounted to theouter body 1.3 and moved proximally, whereby the pre-filled-syringe 2 isretracted to the retracted position PR shown in FIG. 14.

The invention claimed is:
 1. A safety device for a pre-filled syringe,comprising a hollow support body to retain the pre-filled syringetherein, a retaining collar releasably mounted to the support body and arotating collar comprising a central opening for the reception of theprefilled syringe and at least one outwardly protruding guide pin thatprotrudes through a guide track formed into the support body, a guiderail formed into an inner surface of an outer body, whereas the guidetrack comprises an inclined section and an axial section connectedtherewith, whereas the rotating collar is arranged within the supportbody and slidable along an axial length of the support body androtatable around a central axis of the safety device and whereas theretaining collar is movable with respect to the support body in aproximal direction when the retaining collar is released from beingmounted to the support body by the rotating collar.
 2. A safety deviceaccording to claim 1, characterized in that an outer body slidablyarranged relative to the support body abuts the outwardly protrudingguide pin, so that the rotating collar jointly moves together with theouter body along a substantial axial length of the support body.
 3. Asafety device according to claim 1, characterized in that the inclinedsection of the guide track is oriented at an acute angle relative to theaxial section of the guide track, whereas the inclined section isconnected to the axial section by a narrowed section limited by aflexing gate element that is resiliently deflectable.
 4. A safety deviceaccording to claim 3, characterized in that the safety device producesan audible feedback when the guide pin passes the narrowed sectionlimited by the flexing gate element.
 5. A safety device according toclaim 1, characterized in that the rotating collar is biased in theproximal direction by a spring arranged within the support body.
 6. Asafety device according to claim 5, characterized in that a needleshield is slidably arranged relative to the support body, whereas theneedle shield is biased in a distal direction by the spring.
 7. A safetydevice according to claim 6, characterized in that the needle shield hasa central aperture of variable diameter.
 8. A safety device according toclaim 6, characterized in that the needle shield is made by the processof a two-shot injection moulding.
 9. A safety device according to claim1, characterized in that the retaining collar comprises at least oneratchet arm that latches to a locking cut-out formed into an outer bodyto lock the retaining collar relative to the outer body.
 10. A safetydevice according to claim 9, characterized in that the outer bodycomprises a plurality of locking cut-outs that are axially displacedrelative to each other.
 11. A safety device according to claim 1,characterized in that the guide rail comprises a first section that isoriented at an angle less than 90 degrees with respect to the centralaxis and a second section that substantially extends parallel to thecentral axis.
 12. An injection device comprising a safety device and apre-filled syringe, wherein the safety device comprises a hollow supportbody to retain the pre-filled syringe therein, a retaining collarreleasably mounted to the support body and a rotating collar arrangedwithin the support body comprising a central opening for the receptionof the prefilled syringe and at least one outwardly protruding guide pinthat protrudes through a guide track formed into the support body, aguide rail formed into an inner surface of an outer body, whereas theguide track comprises an inclined section and an axial section connectedtherewith, wherein the rotating collar is slidable along an axial lengthof the support body and rotatable around a central axis of the safetydevice and wherein the retaining collar is movable with respect to thesupport body in a proximal direction when the retaining collar isreleased from being mounted to the support body by the rotating collar,and wherein the pre-filled syringe is retractable into the support bodyfrom an advanced position to a retracted position, in which thehypodermic needle is surrounded by the support body.
 13. The injectiondevice according to claim 12, characterized in that the retaining collarcomprises at least one ratchet arm that latches to a locking cut-outformed into an outer body to lock the retaining collar relative to theouter body.
 14. A safety device according to claim 13, characterized inthat the outer body comprises a plurality of locking cut-outs that areaxially displaced relative to each other.
 15. An injection deviceaccording to claim 14, characterized in that the ratchet arm and theplurality of locking cut-outs visually indicate an amount of amedication contained in an inner cavity.